The present invention is based on the concept of fragrance, perfume, emollient or other fabric or skin beneficiating ingredient being released “on demand”, e.g., release at a time of fabric/clothes use and/or wear.
The concept of controlled active release is known in the art, and various methods for achieving this have been developed. One aspect of the controlled release of perfume, for example, is providing slow release of perfume over an extended period of time. This is generally achieved by blending perfume or other fabric or skin beneficiating ingredient with a substance that will, in essence, “trap” the perfume and subsequently release small amounts of perfume over time.
One of the simplest embodiments consists of putting perfume in wax such as described in Canadian Patent No. 1,111,616 to Young, issued November 1981 and in U.S. Pat. No. 6,042,792 to Shefer et al. issued Mar. 28, 2000. Other embodiments encompass the complex technology of microencapsulation, such as in U.S. Pat. No. 4,464,271 to Munteanu et al. issued Aug. 7, 1984 which describes softener compositions containing a non-confined fragrance oil and a fragrance oil entrapped in solid particles.
An example of such microencapsulation technology is embodied in capsules filled with perfume, which are commercially marketed by, e.g., the Reed Pacific Company in Australia or Euracli Company in France. These capsules are adapted to break under friction and provide an instant “burst” of the fragrance when the capsules are ruptured. Microcapsules of the aminoplast type are used in the textile industry, and especially in so-called “intelligent fabrics” or “smart textiles”, such as “Le carre de soie” by Hermes or by DIM (women panties with encapsulated emollient). More particularly, Hermes has commercialized luxurious scarves that release the Hermes perfume by friction created by contact with the neck of the consumer. Dim markets panties which release a relaxing agent for the legs. The microcapsules used are deposited on the fabric surface during the fabric finishing operation which is carried out by the textile manufacturer. These microcapsules are generally removed in the course of subsequent domestic washing; typically capsules can withstand about 5 washes before the fabric or skin beneficiating ingredients lose their intended effect.
From the above, it is clear that the preparation of microcapsules is a known art; preparation methods are, for instance, described in detail in a handbook edited by Simon Benita (“Microencapsulation; Methods and Industrial Applications, Marcel Dekker, Inc. N.Y., 1996), the contents of which are incorporated herein by reference for the preparation techniques described therein.
The preparation process is also the subject of several patents, such as U.S. Pat. No. 3,516,941 to Matson and U.S. Pat. No. 4,976,961 to Norbury and Chang, the disclosures of which are incorporated herein by reference.
Further reference is made to a number of patent publications, which describe the use of encapsulated fragrance in household applications, and more specifically in detergent compositions and in fabric softener products. For example, U.S. Pat. No. 4,145,184 to Brain et al. describes detergent compositions which contain perfumes in the form of friable microcapsules. Preferred materials for the microcapsule shell walls are the aminoplast polymers comprising the reaction product of urea and aldehyde.
U.S. Pat. No. 5,137,646 to Schmidt et al. issued August 1992, describes the preparation and use of perfumed particles, which are stable in fluid compositions and which are designed to break as the perfumed formulation is used, thereby releasing the perfumed particle. More specifically, this patent describes a fabric softener composition comprising one or more fabric- or fiber-softening or antistatic agents, and perfume particles comprising perfume dispersed in a solid core comprising a water-insoluble polymeric carrier material, such as polymers selected from the group consisting of polyethylene, polyamides, polystyrene, polyisoprenes, polycarbonates, polyesters, polyacrylates, vinyl polymers and polyurethanes. These cores are encapsulated by having a friable coating, a preferred coating being an aminoplast polymer which is the reaction product of an amine selected form the group consisting of urea and melamine and an aldehyde selected from the group consisting of formaldehyde, acetaldehyde and glutaraldehyde.
The perfume/controlled release agent may also be in the form of particles mixed into the laundry composition. According to one known method perfume is combined with a water-soluble polymer to form particles which are then added to a laundry composition, as described in U.S. Pat. No. 4,209,417 to Whyte issued June 1980; U.S. Pat. No. 4,339,356 to Whyte issued July 1982; and U.S. Pat. No. 3,576,760 to Gould et al. issued April 1971; and U.S. Pat. No. 5,154,842 to Walley et al. issued October 1992.
The perfume may also be adsorbed onto a porous carrier material, which may be a polymeric material. See, for example, U.S. Pat. No. 5,137,646 to Schmidt et al. Further examples are disclosed in US 2004/0072720 A1, US 2004/0071746 A1, US 2004/0072719 A1, and US 2004/0071742 A1 all of which are incorporated herein by reference. These patent applications describe fragrance materials which are encapsulated within a first polymer selected from the group consisting of a vinyl polymer; an acrylate polymer, melamine formaldehyde polymer, urea formaldehyde polymer and mixtures thereof; said first polymer being further coated with a cationic polyamine or selected from polysaccharides, cationically modified starch, cationically modified guar polysiloxanes, poly diallyl dimethyl ammonium halides, copolymers of poly diallyl dimethyl ammonium chloride, imidazolinium halides.
U.S. Pat. No. 4,234,627 discloses a liquid fragrance coated with an aminoplast shell further coated by a water insoluble meltable cationic coating in order to improve the deposition of capsules from fabric conditioners. U.S. Pat. No. 6,194,375 discloses the use of hydrolyzed polyvinyl alcohol to aid deposition of fragrance-polymer particles from wash products. U.S. Pat. No. 6,329,057 discloses use of materials having free hydroxy groups or pendant cationic groups to aid in the deposition of fragranced solid particles from consumer products.
In our U.S. Pat. No. 6,620,777 we described a fabric softening composition comprising fabric or skin beneficiating ingredient(s) within friable microcapsules of aminoplast polymeric shell.
Despite these and many other disclosures there is an ongoing need for the improved delivery of fragrance materials for various rinse-off products that provide improved performance.